The invention relates to a belt buckle assembly, especially for a seat belt system in a motor vehicle, comprising a belt buckle and a plug-in tongue lockable in the belt buckle.
So far it has been common practice in seat belt systems in motor vehicles that the plug-in tongue of a seat belt can be inserted into and also locked in a corresponding belt buckle at two different orientations. More exactly speaking, the planar plug-in tongue can be inserted into and locked in a slit of the belt buckle at a first orientation or at a second orientation rotated by 180° with respect thereto (relative to the inserting direction).
Such “freedom” of orientation on the one hand has the advantage that when fastening the seat belt the vehicle occupant need not pay attention at which of the two orientations he/she inserts the plug-in tongue into the belt buckle. On the other hand, one of the two possible orientations necessarily entails an undesired twisting of the webbing. Twisting of the webbing does not only result in a loss of comfort, but in this case an optimum contact of the seat belt with respect to the safety of the vehicle occupant is not ensured, either.
Another drawback is resulting for plug-in tongues having a curvature or offset. If the plug-in tongue is inserted into the belt buckle at the wrong orientation, a press button for releasing the locked plug-in tongue arranged next to the inserting slit of the belt buckle is no longer just freely accessible, because the curvature or offset projects above the press button.
DE 38 38 755 A1 illustrates a generic belt buckle assembly in which a buckle tongue is movably supported on a tongue member. The buckle tongue is displaced via an operating element disposed at the tongue member. When the tongue member fully contacts the buckle housing, the operating element is pressed or pushed into the tongue member so that the buckle tongue is pushed or pressed out sufficiently far so that the buckle tongue can be locked in the belt buckle. In a specific embodiment of the known belt buckle assembly plural end pieces provided separately from the belt buckle are provided for shoulder belts and a crotch strap. Due to their recesses adapted to the shape of a shoulder of the buckle tongue the end pieces can be slipped onto the shoulder only in a particular order. In this case the operating element does not contact the belt buckle but a particular one of the end pieces disposed between the belt buckle and the plug-in tongue.
From DE 201 13 868 U1 a plug-in tongue is known which in a transition area between a locking portion adapted to be inserted into a belt buckle and a retaining portion on which a seat belt can be mounted has an encoding projection. Thus the plug-in tongue can be inserted only into a belt buckle associated therewith which is provided with a corresponding recess for the encoding projection. In this way mix-up of the corresponding plug-in tongues is to be excluded in the case of belt buckles that are located next to each other.